Cannon

/kan"euhn/, n.

1. Annie Jump /jump/, 1863-1941, U.S. astronomer.

2. Joseph Gurney /gerr"nee/, ("Uncle Joe"), 1836-1926, U.S. politician and legislator.

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Long-range artillery piece, as distinguished from other big guns such as the howitzer or mortar.

Early cannons, appearing in Europe in the 15th century, were smooth-bored and forged of iron, weighed 6,000–8,000 lbs (2,800–3,600 kg) and were loaded through the muzzle. They were mounted on wheeled carriages, which were thrown backward when the cannon was fired. Rifled bores and breechloading were adopted in the later 19th century, and new mechanisms such as the hydraulic buffer absorbed the recoil. Before 1850 ammunition was either cannister, grapeshot, or round, solid cannonballs and black powder, but rifled bores made possible the use of elongated projectiles, which had a longer range. The shrapnel shell was widely used in the 19th–20th century. Modern cannons, of high-grade steel, are towed on split-trail carriages or are mounted on tracked vehicles; a common calibre is 155 mm (6 in.). Many helicopters, airplanes, and naval vessels are equipped with multibarreled, Gatling-type rotary cannons firing 20-mm exploding shells.

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▪ weapon

 big gun, howitzer, or mortar, as distinguished from a musket, rifle, or other small arm. Modern cannon are complex mechanisms cast from high-grade steel and machined to exacting tolerances. They characteristically have rifled bores, though some contemporary tank-mounted and field artillery guns are smooth-bored.

      Huge artillery pieces appeared in Europe in the 15th century, but until about 1670 the word cannon was applied only to special types of guns. These were usually divided into the cannon royal, or double cannon, which weighed about 8,000 pounds (3,630 kg) and fired a ball weighing 60–63 pounds (27–28 kg); the whole cannon, which weighed about 7,000 pounds and fired a 38–40-pound ball; and the demicannon of about 6,000 pounds, which shot a 28–30-pound ball. Other large guns were not called cannon but bore different names (e.g., culverin) that indicated their size and function.

      During the third quarter of the 17th century, large guns came to be designated by the weight of their projectiles and secondarily by their other characteristics—i.e., whether they were field or siege types, and whether they were called light or heavy, short or long. The name cannon gradually came to be applied to every gun fired from a carriage or fixed mount and with a bore larger than one inch.

      In the 20th century, rapid-firing guns of 20 mm (0.8 inch) and larger mounted in aircraft and firing explosive shells were called automatic cannon. In 1953 the U.S. Army introduced a 280-millimetre gun, the first built to fire atomic-explosive shells; it was called an atomic cannon. Similar weapons were displayed by the U.S.S.R. in 1957. In later years, atomic explosives were fitted into shells small enough to be fired in standard artillery. See artillery.

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